Webmin conf improvements

[JedMeister]

• Write IPv6 firewall rules too.
• Enable HSTS by default
• Redirect HTTP to HTTPS (HTTP just failed before)
• Refactor logging setup - configure log locations in /var/log rather than making symlinks. - note webmin.log is still in default location so that needs a symlink still - however the file is now in /var/log/webmin and link is in /var/lib/webmin
• merge webmin log setup and the general webmin conf script into a single conf script (so can leverage the existing functionality in that)
• fail2ban tweaks (not specific to webmin and probably shouldn't be bundled here, but did the tweak at the same time, so here it is...)